尝试实现RemoteControlClient,但仍然没有获得锁屏控件

我已经浏览了SDK(RandomMusicPlayer)提供的RemoteControlClient示例程序.但是,我不能为我的生活弄清楚如何使用我自己的音乐播放器获得锁屏控制RemoteControlClient.这就是我的音乐播放器服务:

//Request audio focus for playback
int result = audioManager.requestAudioFocus(audioFocusChangeListener,
                                            AudioManager.STREAM_MUSIC,
                                            AudioManager.AUDIOFOCUS_GAIN);

//Check if audio focus was granted. If not, stop the service.
if (result!=AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
    //Stop the service.
    stopSelf();
    Toast.makeText(mContext, R.string.close_other_audio_apps, Toast.LENGTH_LONG).show();
}

ComponentName remoteControlsReceiver = new ComponentName(getPackageName(),      
                                         HeadsetButtonsReceiver.class.getName());

if (mRemoteControlClientCompat == null) {
   Intent remoteControlIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
   remoteControlIntent.setComponent(remoteControlsReceiver);

   mRemoteControlClientCompat = new RemoteControlClientCompat(PendingIntent.getBroadcast(this, 0, remoteControlIntent, 0));
   RemoteControlHelper.registerRemoteControlClient(audioManager, mRemoteControlClientCompat);
   audioManager.registerMediaButtonEventReceiver(remoteControlsReceiver);
}

这基本上就是SDK示例所做的(据我所知).我已经确认我的应用程序能够获得音频焦点.我完成了我的作业,并且知道需要音频专注才能使用.我到底错过了什么？任何指向正确方向的人都非常感激.:)